Dihexa: Benefits, Dosage and Side Effects in 2026
Dihexa is a lab-made angiotensin IV analog sold as a research compound for memory and focus68. It has never been tested in people1, and FDA has no human exposure data for it2. Two papers from the group that developed it were retracted in 2025 for falsified or fabricated data34. It is not approved.
Other names: N-hexanoic-Tyr-Ile-(6) aminohexanoic amide; PNB-040869. Related: Semax, Selank and Pinealon.
Last updated November 7, 2026 by the Prof. Peptide editorial team
What is Dihexa?
Dihexa is a small modified peptide, N-hexanoic-Tyr-Ile-(6) aminohexanoic amide, made at Washington State University from the angiotensin IV fragment to be stable and to cross into the brain68. Two of its founding papers were retracted in 2025, and the paper that first names it carries a Notice of Concern345.
Where to buy Dihexa?
Dihexa has no prescription product anywhere in the sources read. Research-grade Dihexa is sold by specialty peptide vendors for laboratory use only, with no label behind it. The vendors listed here sell it, each with Prof. Peptide's code. Each vendor name links to its Prof. Peptide page, with the vendor's catalogue, testing and shipping details.
How much does Dihexa cost?
Dihexa's research-grade prices are compared below by vial size across the vendors Prof. Peptide tracks, with the date the prices were read. No approved Dihexa product exists to compare against. Each row lists the vendor, the vial size, the price per mg after Prof. Peptide's code, stock and a Shop button.
Dihexa costs from $2.40 to $25.20 per mg after Prof. Peptide's code, across 7 listings from 7 vendors, with prices as of November 7, 2026; the median listing is $6.44 per mg. The 5 lowest prices per mg are listed first below, each with the vendor's code and Shop button, and every other listing is one click away.
Prices as of November 7, 2026
Median listed price per mg: $6.50 (August 10, 2026, 10 listings) → $7.16 (November 7, 2026, 7 listings); fewer listings were on file at the end of the period.
What are Dihexa's uses and reported benefits?
Dihexa is used for memory, focus and learning, and clinics describe it as supporting neuron growth, memory and neuroprotection10111213. No benefit has been measured in people: the research has not reached people, and the papers behind its reputation for reversing memory loss were retracted134.
Clinical reports
- Memory and learning: clinics describe it as studied for, or improving, memory, learning and creative thinking101112.
- Focus and cognitive clarity: clinics list focus and cognitive clarity, with neuroprotection1213.
No clinic page read states a side effect or caution for Dihexa (0 of 9 pages)10111213.
How does Dihexa work?
Dihexa is proposed to act on the hepatocyte growth factor (HGF) and its receptor c-Met in the brain, encouraging nerve cells to branch and form new connections, as the group that developed it describes8. That account rests partly on a paper retracted in 20253; an independent study linked it to the PI3K/AKT signalling pathway7.
How is Dihexa dosed?
No trial or label sets a dose for Dihexa1. Of nine clinic pages read, two describe it as one oral capsule a day1011. One lists capsule strengths of 2,000, 5,000, 10,000 and 25,000 mcg (2, 5, 10 and 25 mg), varied by the patient's condition11.
The same clinic also lists a topical gel applied once or twice a day11. The only doses in the literature come from research outside people, set out further down the page.
Clinic practice is reported as published; it is not a trial result and not advice1011.
Need to calculate a dose?
Use the Prof. Peptide dosage calculator for accurate reconstitution and dosing math.
Open CalculatorHow is Dihexa taken?
Clinics administer Dihexa orally, as a daily capsule1011; one also offers it as a topical gel11. No route has been studied in people1; studies outside people administered it orally or by injection7. Research-grade Dihexa is sold for laboratory use only, labelled by its vendors as not for human consumption.
What are the side effects of Dihexa?
Is Dihexa legal?
Dihexa is not approved for use in people. FDA lists dihexa acetate among bulk drug substances “nominated but withdrawn” from Category 2 and states it has not identified any human exposure data on drug products containing it, by any route2. Research-grade Dihexa is sold for laboratory use only.
No clinic statement on Dihexa's legal or regulatory status was found after searching 9 clinic pages that list it10111213.
The research record
- April 2025: the Journal of Pharmacology and Experimental Therapeutics retracted a 2014 paper on Dihexa's memory and synapse effects; a Washington State University investigation found figures containing “falsified and/or fabricated data”3.
- April 2025: the same journal retracted a 2012 paper developing the angiotensin IV analogs Dihexa belongs to4.
- 2021: Notices of Concern on three of the group's papers, including the 2013 paper that first names Dihexa, which has not been retracted as of November 4, 202656.
What do human studies show about Dihexa?
Dihexa has no human study. A literature search on November 4, 2026 for Dihexa and its chemical names returned 123 records; limited to patients, volunteers or clinical trials it returned 9, none a study of Dihexa in people1. FDA likewise reports no human exposure data2. The registered-trial database was not searched for this profile.
What does animal and lab research show about Dihexa?
Dihexa's research is in mice, rats and cells. In an independent 2021 study of a mouse model of Alzheimer's disease, Dihexa given by mouth restored spatial learning in a water-maze test and lowered the inflammatory signals IL-1β and TNF-α7. The group's earlier memory and synapse papers include the two retracted in 202534.
Animal and cell results do not show that the same happens in people.
Dihexa FAQ
What is Dihexa?
Dihexa is a lab-made analog of the hormone fragment angiotensin IV, developed at Washington State University and sold as a research compound for memory68. Its research has not reached people1, two of the papers behind its reputation were retracted in 202534, and it is not approved. See What is Dihexa?
Has Dihexa been tested in humans?
No. A literature search on November 4, 2026 found 123 records on Dihexa and its chemical names, none a study in people1, and FDA states it has not identified any human exposure data for it by any route2. See What do human studies show about Dihexa?
Why were the Dihexa studies retracted?
In April 2025 the Journal of Pharmacology and Experimental Therapeutics retracted two papers from the group that developed Dihexa, after a Washington State University investigation found figures containing falsified or fabricated data34. A third paper, the one that first names Dihexa, has carried a Notice of Concern since 202156. See Is Dihexa legal?
Is Dihexa FDA approved?
No. FDA lists dihexa acetate among bulk drug substances “nominated but withdrawn” from Category 2 and states it lacks important information on its safety, including whether it would harm people2. No approved Dihexa product exists anywhere in the sources read. See Is Dihexa legal?
Where can I buy Dihexa?
Dihexa is not approved for use in people, so no prescription product exists. Research-grade material is sold by vendors for laboratory use only. Where to buy Dihexa? lists vendors with Prof. Peptide's code, and How much does Dihexa cost? compares prices. The verified discount codes page lists every vendor with a code.
References
- Europe PMC literature search: dihexa and its chemical namesDatabaseEurope PMC. Searched November 4, 2026: dihexa OR “N-hexanoic-Tyr-Ile-(6) aminohexanoic amide” OR “Nle1-angiotensin IV” OR “Nle-AngIV” OR “angiotensin IV analog(s)” OR “angiotensin IV-derived”, 123 records; limited to patients, healthy volunteers or clinical trials, 9, none a human study of Dihexa.europepmc.org →
- Certain bulk drug substances for use in compounding that may present significant safety risks (Category 2)RegulatorU.S. Food and Drug Administration. Content current as of April 22, 2026; read November 4, 2026.Key finding: “Dihexa acetate FDA has not identified any human exposure data on drug products containing dihexa acetate administered via any route of administration. FDA lacks important information regarding any safety issues raised by dihexa acetate, including whether it would cause harm if administered to humans.”fda.gov →
- Retraction notice: The Procognitive and Synaptogenic Effects of Angiotensin IV-Derived Peptides Are Dependent on Activation of the Hepatocyte Growth Factor/c-Met SystemRetractionJ Pharmacol Exp Ther. 2025 (notice); retracts Benoist CC, et al. J Pharmacol Exp Ther. 2014;351:390-402. Read November 4, 2026.Key finding: “This article has been retracted at the request of the Editor. Following an investigation by Washington State University, Figures 1B, 2A/C, and data in the subsequent erratum submission for the article have been found to contain falsified and/or fabricated data.”PubMed 40312093 →Full text (PMC13095468) →DOI →
- Retraction notice: Development of Angiotensin IV Analogs as Hepatocyte Growth Factor/Met ModifiersRetractionJ Pharmacol Exp Ther. 2025 (notice); retracts Kawas LH, et al. J Pharmacol Exp Ther. 2012;340:539-548. The record was read on November 4, 2026.PubMed 40312092 →DOI →
- Notices of Concern on three J Pharmacol Exp Ther papers (2012, 2013, 2014)Notice of ConcernJ Pharmacol Exp Ther. 2021. PMIDs 34551987 (Benoist 2014), 34551990 (Kawas 2012) and 34551989 (McCoy 2013). The records were read on November 4, 2026.PubMed 34551989 →
- Evaluation of metabolically stabilized angiotensin IV analogs as procognitive/antidementia agentsResearch paperMcCoy AT, et al. J Pharmacol Exp Ther. 2013. The paper that names Dihexa; under a 2021 Notice of Concern, not retracted as of November 4, 2026.Key finding: “an orally active, blood-barrier permeant, metabolically stabilized analog, N-hexanoic-Tyr-Ile-(6) aminohexanoic amide (dihexa)”PubMed 23055539 →
- AngIV-Analog Dihexa Rescues Cognitive Impairment and Recovers Memory in the APP/PS1 Mouse via the PI3K/AKT Signaling PathwayAnimal studySun X, Deng Y, Fu X, Wang S, Duan R, Zhang Y. Brain Sci. 2021. Abstract read November 4, 2026.Key finding: “Dihexa restored spatial learning and cognitive functions in the Morris water maze test”; “markedly reduced levels of the pro-inflammatory cytokines IL-1β and TNF-α.”PubMed 34827486 →
- The Brain Hepatocyte Growth Factor/c-Met Receptor System: A New Target for the Treatment of Alzheimer's DiseaseReviewWright JW, Harding JW. J Alzheimers Dis. 2015. A review by the group whose papers were later retracted; cited for how that group describes the compound.PubMed 25649658 →
- PNB-0408 (Dihexa) in a rat model of Huntington's diseaseAnimal studyWells, Azzam, Hiller, Sardinia. J Huntingtons Dis. 2024. Cited for the name: “N-hexanoic-Tyr-Ile-(6)-amino hexanoic amide (PNB-0408), also known as Dihexa.”PubMed 38489193 →
- Peptide therapy, El PasoClinicSolas Health & Wellness. Cited for “Studied for cognitive enhancement, memory support, and neuroprotection” and “Taken as a daily oral capsule.” Read November 4, 2026.solasclinic.com →
- Peptides at Azani Medical SpaClinicAzani Medical Spa. Cited for “It helps improve memory and creative thinking and learning skills” and “The usual oral dose of Dihexa is 1 capsule daily, varying according to the patient’s condition”, capsules of “2 mg, 5 mg, 10 mg, and 25 mg”, and a topical dose of “1-2 applications per day”. Read November 4, 2026.azanimedicalspa.com →
- Peptide therapyClinicAgeRejuvenation. Cited for “studied for its ability to activate hepatocyte growth factor receptors in the brain, which may support neuron growth, memory, and focus.” Read November 4, 2026.agerejuvenation.com →
- Peptides: the next frontier in precision longevity medicineClinicCenegenics. Cited for “Semax and Dihexa enhance cognitive clarity and neuroprotection, supporting neurotransmitter signaling and synaptic plasticity.” Read November 4, 2026.cenegenics.com →
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